Solution-processable conjugated polymer and/or copolymer semiconductors have attracted attention in the art due to their potential applications in making large area, flexible, and low-cost electronic devices, including organic light emitting diodes (OLEDs), solar cells and/or transistors. Variation of the number and kind of copolymer subunits has been used to tune the electronic energy levels of the conjugated copolymers so as to improve the efficiency of the absorption of solar radiation, and/or facilitate charge transport in the solid state polymer semiconductors. Incorporation of heterocyclic aromatic subunits and/or optimizing the polymer chain length have been shown to sometimes enhance intermolecular π-stacking interactions between polymer chains that can induce at least some long range 3-D or 2-D order and/or crystallinity in the solid state, and potentially improve charge carrier mobilities and other desirable electronic properties of the resulting copolymers, and organic electronic devices derived from them. However, given the complexity of the interactions in the relevant electronic states of the polymers, and the complexity of the packing and other physical interactions in the solid state, the predictability of the ultimate solid state properties remains low, and many unexpected results, both positive and negative, are often observed in practice.
Some such polymers and/or copolymers known in the prior art, notably some polythiophene copolymers, have achieved reasonably high hole carrier mobilities and good performance when used to make transistors, or encouraging efficiencies in solar cells for converting solar radiation to electrical energy (3-5%), but most or all such prior art polymers lack good thermal or oxidative stability, or the practical processability characteristics needed in order to make commercially practical electronic devices.
PCT Publication WO 2007/145482 disclosed some broad genera of copolymers comprising thiazolothiazole subunits, and electronic devices comprising, but did not disclose or suggest the copolymers described and claimed herein which comprise or silylene-bithiophene subunits, or the unexpectedly good performance obtained with such copolymers.
US Patent Publication US 2009/0230386 described copolymers comprising benzobisthiazole subunits, and transistors comprising those copolymers, but did not disclose or suggest the use of those copolymers in solar cell devices.
Jung et al (J. Phys. Chem. C 2010, 114, 16843-16848) disclosed certain copolymers comprising thiazolothiazole subunits, and their use in solar cell devices, but did not disclose or suggest the copolymers described and claimed herein which comprise or silylene-bithiophene subunits, or the unexpectedly good performance obtained with such copolymers.
Shi et al (Chem. Eur. J. 2010, 16, 3743-3752) disclosed certain copolymers comprising thiazolothiazole subunits, and their use in transistors and solar cell devices, but did not disclose or suggest the copolymers described and claimed herein which comprise or silylene-bithiophene subunits, or the unexpectedly good performance obtained with such copolymers
Nevertheless, there remains an as yet unsatisfied need in the art for new and improved polymeric and/or copolymeric materials, and/or solid materials or compositions derived therefrom that can provide the needed properties for electron or hole transport, as well as improved processability, performance, cost, and thermal and oxidative stability for use in organic electronic devices, especially transistors and solar cells. It is toward solving such as yet unsolved problems that the various embodiments of the various inventions described below are directed.